The name Flex refers to 9 different artists/groups.

1) Flex is the name of the Panamanian singer who''s debut album "Te Quiero" is described as “Romantic Reggaeton". His other stage name, which he still uses in most Latin American countries, is Nigga.

2) Flex is also the name of a group out of Petion-Ville, Haiti whose music style is a mix of Rap, Ragga, Dancehall, R&B, Soul. Throughout its history the band has seen members come and go. Some of the artists who were a part of Flex are: King D, BIC, T-Danash, Ashte...
The band has released 2 albums before the members went their separate ways: "Work So Hard" in 1998 and "Pouki?" in 2001.

3) Flex is also a member of the Dutch Rap Group THC. His Younger brother RBDjan is also in that group which focuses mainly on Dutch Gangster rap.

4) Flex is a Canadian hip hop artist from London, Ontario.

5) Flex is also the name of a Lithuanian pop group.

6) A Hardcore band from Socal, whose music can be found http://flexsbhc.bandcamp.com/

7) Folk/Rock band from Germany with patriotic themes.

8) Norwegian rapper from Olsvik, Bergen.

9) Industrial metal band from France